Inflammation involves an innate and adaptive immune response that is required for fighting infection. However, when the inflammation becomes unchecked autoimmune or autoinflammatory diseases, neurodegenerative disease, and even cancer can develop. It is well established that inhibiting activity of proinflammatory cytokines such as IL1, TNF-alpha, IL6, IL12, IL17, IL18, or IL23 reduces inflammation and suppresses specific pathways that activate immune cells.
Interleukin 23 (IL23) is a heterodimeric cytokine consisting of two subunits, p40 and p19. The p19 subunit is also referred to as IL-23A. While the p19 subunit is unique to IL23, the p40 subunit is shared with the cytokine IL12. IL23 is emerging as a key regulator of pathogenic Th17, γδ T and innate lymphoid cells (ILCs) driving the production of IL17, IL22 and other cytokines that lead to local tissue inflammation and damage. IL23 promotes upregulation of the matrix metalloprotease MMP9, increases angiogenesis, reduces CD8+ T cell infiltration, and has been implicated in the development of cancerous tumors. In addition, in conjunction with IL6 and TGF-beta1, IL23 stimulates naive CD4+ T cells to differentiate into Th17 cells. In turn, the Th17 cells produce IL17, a proinflammatory cytokine that enhances T cell priming and stimulates the production of proinflammatory cytokines such as IL1, IL6, TNF-alpha, NOS-2, and also induces expression of chemokines resulting in inflammation and disease pathogenesis. IL23 exerts its effects via a cell surface receptor composed of the IL12β1 subunit of IL12 receptor partnered with a unique IL23R subunit. Expression of the IL23R is restricted to specific populations of immune cells and is found primarily on subsets of T cells (αβ and γδ TCR+) and NK cells.
In mice, genetic ablation of the IL23p19 gene results in selective loss of IL23 function accompanied by severely compromised T-dependent immune responses, including reduced production of antigen-specific immunoglobulins and impaired delayed type hypersensitivity responses (Ghilardi N, et al. (2004) J. Immunol. 172(5): 2827-33). Knockout mice deficient in either IL23p40 or IL23p19, or in either subunit of the IL23 receptor (IL23R and IL12-beta1), develop less severe symptoms in animal models of multiple sclerosis, arthritis and inflammatory bowel disease. Similar results have been obtained using an antibody specific for IL23p19 in EAE and a T cell mediated colitis model further substantiates the role of IL23 in these disease settings (Chen Y. et al. (2006) J. Clin. Invet. 116(5):1317-26; Elson C O. et al. (2007) Gastroenterology 132(7): 2359-70). This highlights the importance of IL23 in chronic inflammation (Langowski et al. (2006) Nature 442 (7101): 461-5; Kikly K, et al. (2006) Curr. Opin. Immunol. 18 (6): 670-5). In addition, elevated IL23 production has been implicated as being a major factor in inflammatory arthritis and in inflammatory autoimmune diseases (Adamopoulos et al. (2011) J. Immunol. 187: 593-594; and Langris et al. (2005) J. Exp. Med. 201:233-240). A connection between IL23, its downstream cytokine IL22, and bone formation has been published in a mouse model system in which IL23 is overexpressed (Sherlock et al. (2012) Nat. Med. 18: 1069-76).
The homotrimeric TNF-α cytokine is expressed predominantly by macrophages, lymphocytes, endothelial cells and fibroblasts and binds two distinct receptors: TNFRI, expressed on nearly all cell types and TNFRII, with more limited expression on immune cells (CD4+ T cells, NK cells). Like many TNF superfamily members, TNF-α exists as both membrane and soluble forms, the soluble form arising from cleavage of the membrane form by the ADAM12 metalloprotease (TACE, TNFα converting enzyme). Both membrane-bound and soluble forms of the cytokine are biologically active.
Tumor necrosis factor (TNF-alpha/TNF-α) is a proinflammatory cytokine that stimulates the acute phase of inflammation. Tumor necrosis factor increases vascular permeability through induction of IL8, thereby recruiting macrophage and neutrophils to a site of infection. Once present, activated macrophages continue to produce TNF-alpha, thereby maintaining and amplifying the inflammatory response. The primary role of TNF-alpha is the regulation of immune cells; however, TNF-alpha is also involved in the regulation of a wide spectrum of biological processes including cell proliferation, differentiation, apoptosis, lipid metabolism, and coagulation. TNF-alpha is able to induce inflammation, induce apoptotic cell death, inhibit tumorigenesis and inhibit viral replication.
Dysregulation of TNF-alpha production has been implicated in a variety of human diseases, including autoimmune disease (e.g. rheumatoid arthritis (RA), Crohn's disease, multiple sclerosis), inflammatory bowel disease (IBD), ulcerative colitis, psoriasis, toxic shock, graft versus host disease, insulin resistance, Alzheimer's disease, cancer, and major depression (Swardfager W, et al. (2010) Biol Psychiatry 68 (10): 930-941; (Locksley R M, et al. (2001) Cell 104 (4): 487-501; Dowlati et al., (2010) Biol Psychiatry 67 (5): 446-457; Brynskov J. et al. (2002) Gut 51 (1): 37-43).
Antibodies have been used as biologic therapies for inhibition of TNF-alpha and IL23 in order to treat a variety of inflammatory diseases. Infliximab (Centocor, Malvern, Pa.) described in U.S. Pat. Nos. 6,277,969, 6,284,471, and 6,790,444, is a chimeric anti-TNF-alpha monoclonal IgG antibody bearing human IgG4 constant and mouse variable regions and is used clinically to treat rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, ulcerative colitis and plaque psoriasis. Monoclonal antibody adalimumab (clone D2E7; Abbott Laboratories, Abbott Park, Ill.) described in U.S. Pat. No. 6,090,382, is an anti-TNF-alpha therapy used clinically to treat rheumatoid arthritis, Crohn's disease, psoriasis, psoriatic arthritis, ankylosing spondylitis, and juvenile idiopathic arthritis. Golimumab is a TNF-alpha blocker used to treat rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis. In addition, human monoclonal antibody ustekinumab (Centocor, Inc, Malvern, Pa.), described in U.S. Pat. Nos. 6,902,734 and 7,166,285, is directed against interleukin 12 and interleukin 23 (specifically the p40 subunit), is clinically used to treat severe plaque psoriasis, and is further being investigated for the treatment of psoriatic arthritis, multiple sclerosis, and sarcoidosis. However, anti-TNF-α therapies have reported side effects [see for example: Keane J et al. (2001)]. Tuberculosis is associated with infliximab, a tumor necrosis factor α-neutralizing agent. N Engl J Med 345 (15):1098-1104; Scheinfeld N. (2005) Adalimumab: a review of side effects. Expert Opin Drug Saf. 4(4):637-41; Chovel-Sella A et al. (2012) Clinical efficacy and adverse effects of golimumab in the treatment of rheumatoid arthritis. Isr Med Assoc J. 14(6):390-4]. Identification of more efficacious treatments should allow for administration of reduced dosages, as well as lower costs associated with the treatment.
There remains a need for compositions with increased efficacy for treating and preventing autoimmune or inflammatory diseases.